In recent years, disk drives such as a magnetic disk drives and an optical disk drives are widely used as an external recording device and an image recording device of a computer.
The magnetic disk drive generally includes a magnetic disk placed in a case, a spindle motor that supports and rotates the magnetic disk, and a head gimbal assembly (HGA). The head gimbal assembly includes a suspension that is attached to a tip section of an arm, a flexure (a wiring member) that is provided on the suspension and is connected to the outside, and a magnetic head that is supported on the suspension with a gimbal section of the flexure. A wiring of the flexure is electrically connected to the magnetic head. Moreover, the suspension includes a load beam and a base plate fixed to a base end side of the load beam, and the base plate is fixed to the tip section of the arm.
In recent years, an HGA in which a thin-film piezoelectric element (PZT element) is mounted on a gimbal section of a flexure and a microscopic displacement is caused in a seek direction of a magnetic head by an expansion and contraction of the piezoelectric element, has been proposed. With this HGA, the operation of the magnetic head may be controlled by varying a voltage applied to the piezoelectric element.
However, in the above-described HGA, when the piezoelectric element expands or contracts by a voltage application, the piezoelectric element bends in a thickness direction thereof and an out-of-plane vibration is sometimes generated. The out-of-plane vibration is transferred to a load beam via the flexure, unnecessarily exciting the resonance frequency of the load beam. As a result, the positioning accuracy of the magnetic head is reduced.